1. Field of the Invention
The present invention relates to a bearing device with a sensor such as, for example, a wheel support bearing assembly with a revolution sensor for use in an automotive vehicle and in any other field of application.
2. Description of the Prior Art
Wheel support bearing assemblies used in automotive vehicles make use of a revolution sensor for detecting the number of revolutions of a vehicle wheel for the purpose of controlling an anti-lock brake device and any other purpose. The revolution sensor is made up of a magnetic encoder of a ring-shaped configuration fitted to an inner race, which serves as a rotatable raceway member, and a sensor fitted to an outer race, which serves as a stationary raceway member, for detecting the magnetic encoder in a non-contact fashion.
As a first example of configuration for fitting the sensor, the use of a sensor mounting member prepared by pressing a sheet metal has been suggested (See, for example, the Japanese Laid-open Patent Publication No. 6-308145.). This suggested sensor mounting member includes a cutout hole formed in an annular support that is mounted on and, hence, fitted to the outer race, a pair of slide groove forming portions defined on respective side edges of the cutout hole for engagement with side portions of the sensor, and a tongue provided in a lower edge of the cutout hole for urging against a rear face of the sensor.
As a second example of configuration for fitting the sensor, the example is known, in which a retaining member of an arcuate configuration is molded integrally with an outer race mounting tube of an annular configuration mountable on the outer race to form a sensor holder and a sensor element is embedded in the retaining member provided in a portion of this sensor holder (See, for example, the Japanese Laid-open Patent Publication No. 2003-254985).
Although the above described first example of configuration, in which the sensor is inserted in between the slide groove forming portions and is then urged by the tongue has such an advantage as to enable it to be simply mounted, there is a possibility of accidental separation. Also, since the wheel support bearing assembly is placed under the environment tending to be exposed to the road surface, grits and sands are apt to ingress in between the sensor and the magnetic encoder, resulting in the possibility of breakage.
Also, the above described second example of configuration is such that since the retaining member of the sensor holder, in which the sensor element is embedded, and the outer race mounting tube are molded integrally with each other, the sensor holders of varying sizes must be manufactured for each size of the bearing devices with sensors, which vary in size depending on the type of automotive vehicles and the bearing capacity, resulting in increase of the cost.